It is known to inflate an inflatable vehicle occupant protection device to help protect a vehicle occupant. One particular type of inflatable vehicle occupant protection device is an inflatable curtain that inflates away from the roof of the vehicle in a downward direction and inside the passenger compartment between a vehicle occupant and the side structure of the vehicle. A known inflatable curtain is inflated from a deflated condition by inflation fluid directed from an inflator to the inflatable curtain.